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%I #11 Jan 08 2019 06:45:29
%S 1,3,4,12,25,52,121,261,576,1280,2809,6204,13689,30167,66564,146804,
%T 323761,714136,1575025,3473817,7661824,16898560,37271025,82203912,
%U 181306225,399883707,881971204,1945248444,4290381001,9462732780
%N Number of (n+1) X (1+1) arrays of permutations of 0..n*2+1 with each element having directed index change 2,-1 1,0 2,1 0,-1 -2,-2 or -1,0.
%H R. H. Hardin, <a href="/A264484/b264484.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 2*a(n-1) + a(n-3) - 2*a(n-4) + 4*a(n-5) + a(n-6) - a(n-9).
%F Empirical g.f.: x*(1 + x - 2*x^2 + 3*x^3 - x^7) / ((1 - 2*x - x^3)*(1 + 2*x^4 - x^6)). - _Colin Barker_, Jan 08 2019
%e Some solutions for n=4:
%e ..2..3....2..3....1..3....2..3....1..3....1..3....2..3....2..3....2..3....2..3
%e ..0..1....4..5....4..5....0..5....0..5....0..5....4..1....0..1....0..1....4..1
%e ..6..7....1..0....6..0....1..7....2..7....6..7....5..0....6..7....5..7....6..0
%e ..8..5....8..9....8..2....8..9....8..9....8..2....8..9....8..9....8..9....8..9
%e ..9..4....6..7....9..7....6..4....6..4....9..4....6..7....5..4....6..4....5..7
%Y Column 1 of A264490.
%K nonn
%O 1,2
%A _R. H. Hardin_, Nov 14 2015
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